cavalary team, HELP!

-Can't really compare Camus, a cavalier, to Hardin, an armored unit. Way unfair in comparison, lol.

-Reinhardt... sure, I guess. I personally dislike using him, but he's not a bad option.

-Frederick is a good option. Nothing wrong with using him, but you already have a Gunnthra, so I dunno if you'd want 2 green units on your team.

-Roderick, in my opinion, is a really good unit. Decent attack, good speed AND has a Firesweep Lance.

-L'Arachel is probably better as a Bladetome mage rather than using Ivaldi sinse it not only increases her defense (probably her WORST stat), but it also relies on the enemy's HP.

-Xander's main point is defense, hence his 37 base defense stat. Even then, he has access to Hone Cavalry, so it's really not as bad as you're making it out to be, lol.

Out of the units, I'd personally use...
Bladetome L'Arachel
Brave Axe+ Frederick
Xander
Roderick

I don't know why you are making such a big deal about Xander's and Camus' Atk stats. Sure, it might be lower than the other DC users, but they have an advantage in that they are really easy to buff. (Hone Cavalry requires less setup, buffs both Atk and Spd, and is much easier to get than Atk Tactic.)

Anyway, Reinhardt (as long as he doesn't have -Atk) is always a solid option. If you need another good tank to go with Sigurd, then Camus is great because he comes with Grani's Shield which will neutralize all of the Cavalry-effective weapons that IS loves to put in the GHB maps.

Which Reinhardt? In my opinion, your team is already stacked, my premier cavalry team uses those same 3 as they are some of the best calvary around. Based upon your choices presented, I would simply reccommend any of the blue units to balance out your team and meet all triangle checks. Blue Reinhardt is top choice, but with those IVs, your L'Arachel might be better for the time being. Perhaps not to your liking, but would you consider a calvary healer?

Try to roll for a +atk Reinhart and build him. He's really op and will make your Carly team better. For the rest, keep sigurd gunthra and brave Lyn. They are all the best in their color categories.

Xander(will primarily be used to get your nukers out of harm's way)-and deal with pesky greens with TA ( A-slot skill)
L'arachel(is a great bladetome user)- will mostly be your main damage dealer to high defense units
Gunnthra(is primarily a buffer and same with xander-a unit you use to get your nukers out of harm's way while also dealing some debuffs to enemy opposition)
B.Lyn-your main physical nuker- I would change her weapon to brave bow in this team.

-you can use your wind blessings.
-you have 2 primary ways of dealing damage (physical and magical)
-you also have a bait type unit in xander and a unit that you can use to bait and has a debuff ability.
-I would suggest to give xander and gunnthra -reposition. While B.Lyn and L'arachel gets Drawback.

I have all of those units you listed and I would say this is probably one of the best you could use atm.

-IF you plan to make Gunnthra a bladetome user, I would remove L'arachel and replace her with Camus and keep the other two in the team. Same strategy. Camus becomes your bait unit to keep your nukers safe. While Gunnthra becomes your magical nuke.

Good Luck!

Honestly, with Sigurd, Lyn and gunnthra, Camus is literally the perfect fit. DC, blue, and you already have a nuke and a semi-nuke. Reinhardt would make your team too frail.